| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20210318180824.GA1532406@xps15>
Date: Thu, 18 Mar 2021 12:08:24 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Suzuki K Poulose <suzuki.poulose@....com>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
mike.leach@...aro.org, anshuman.khandual@....com,
leo.yan@...aro.org
Subject: Re: [PATCH v4 18/19] coresight: sink: Add TRBE driver
Good morning,
On Thu, Feb 25, 2021 at 07:35:42PM +0000, Suzuki K Poulose wrote:
> From: Anshuman Khandual <anshuman.khandual@....com>
>
> Trace Buffer Extension (TRBE) implements a trace buffer per CPU which is
> accessible via the system registers. The TRBE supports different addressing
> modes including CPU virtual address and buffer modes including the circular
> buffer mode. The TRBE buffer is addressed by a base pointer (TRBBASER_EL1),
> an write pointer (TRBPTR_EL1) and a limit pointer (TRBLIMITR_EL1). But the
> access to the trace buffer could be prohibited by a higher exception level
> (EL3 or EL2), indicated by TRBIDR_EL1.P. The TRBE can also generate a CPU
> private interrupt (PPI) on address translation errors and when the buffer
> is full. Overall implementation here is inspired from the Arm SPE driver.
>
> Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
> Cc: Mike Leach <mike.leach@...aro.org>
> Cc: Suzuki K Poulose <suzuki.poulose@....com>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
> ---
> Changes:
> - Replaced TRBLIMITR_LIMIT_SHIFT with TRBBASER_BASE_SHIFT in set_trbe_base_pointer()
> - Dropped TRBBASER_BASE_MASK and TRBBASER_BASE_SHIFT from get_trbe_base_pointer()
> - Indentation changes for TRBE_BSC_NOT_[STOPPED|FILLED|TRIGGERED] definitions
> - Moved DECLARE_PER_CPU(...., csdev_sink) into coresight-priv.h
> - Moved isb() from trbe_enable_hw() into set_trbe_limit_pointer_enabled()
> - Dropped the space after type casting before vmap()
> - Return 0 instead of EINVAL in arm_trbe_update_buffer()
> - Add a comment in trbe_handle_overflow()
> - Add a comment in arm_trbe_cpu_startup()
> - Unregister coresight TRBE device when not supported
> - Fix potential NULL handle dereference in IRQ handler with a spurious IRQ
> - Read TRBIDR after is_trbe_programmable() in arm_trbe_probe_coresight_cpu()
> - Replaced and modified trbe_drain_and_disable_local() in IRQ handler
> - Updated arm_trbe_update_buffer() for handling a missing interrupt
> - Dropped kfree() for all devm_xxx() allocated buffer
> - Dropped additional blank line in documentation coresight/coresight-trbe.rst
> - Added Documentation/ABI/testing/sysfs-bus-coresight-devices-trbe
> - Changed CONFIG_CORESIGHT_TRBE options, dependencies and helper write up
> - Added comment for irq_work_run()
> - Updated comment for minumum buffer length in arm_trbe_alloc_buffer()
> - Dropped redundant smp_processor_id() from arm_trbe_probe_coresight_cpu()
> - Fixed indentation in arm_trbe_probe_cpuhp()
> - Added static for arm_trbe_free_buffer()
> - Added comment for trbe_base element in trbe_buf structure
> - Dropped IS_ERR() check from vmap() returned pointer
> - Added WARN_ON(trbe_csdev) in arm_trbe_probe_coresight_cpu()
> - Changed TRBE device names from arm_trbeX to just trbeX
> - Dropped unused argument perf_output_handle from trbe_get_fault_act()
> - Dropped IS_ERR() from kzalloc_node()/kcalloc() buffer in arm_trbe_alloc_buffer()
> - Dropped IS_ERR() and return -ENOMEM in arm_trbe_probe_coresight()
> - Moved TRBE HW disabling before coresight cleanup in arm_trbe_remove_coresight_cpu()
> - Changed error return codes from arm_trbe_probe_irq()
> - Changed error return codes from arm_trbe_device_probe()
> - Changed arm_trbe_remove_coresight() order in arm_trbe_device_remove()
> - Changed TRBE CPU support probe/remove sequence with for_each_cpu() iterator
> - Changed coresight_register() in arm_trbe_probe_coresight_cpu()
> - Changed error return code when cpuhp_setup_state_multi() fails in arm_trbe_probe_cpuhp()
> - Changed error return code when cpuhp_state_add_instance() fails in arm_trbe_probe_cpuhp()
> - Changed trbe_dbm as trbe_flag including its sysfs interface
> - Handle race between update_buffer & IRQ handler
> - Rework and split the TRBE probe to avoid lockdep due to memory allocation
> from IPI calls (via coresight_register())
> - Fix handle->head updat for snapshot mode.
> ---
> .../testing/sysfs-bus-coresight-devices-trbe | 14 +
> .../trace/coresight/coresight-trbe.rst | 38 +
> drivers/hwtracing/coresight/Kconfig | 14 +
> drivers/hwtracing/coresight/Makefile | 1 +
> drivers/hwtracing/coresight/coresight-trbe.c | 1149 +++++++++++++++++
> drivers/hwtracing/coresight/coresight-trbe.h | 153 +++
> 6 files changed, 1369 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-coresight-devices-trbe
> create mode 100644 Documentation/trace/coresight/coresight-trbe.rst
Please spinoff these two file in a separate patch and CC Jon Corbet and the
linux-doc mailing list.
> create mode 100644 drivers/hwtracing/coresight/coresight-trbe.c
> create mode 100644 drivers/hwtracing/coresight/coresight-trbe.h
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-trbe b/Documentation/ABI/testing/sysfs-bus-coresight-devices-trbe
> new file mode 100644
> index 000000000000..ad3bbc6fa751
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-trbe
> @@ -0,0 +1,14 @@
> +What: /sys/bus/coresight/devices/trbe<cpu>/align
> +Date: March 2021
> +KernelVersion: 5.13
> +Contact: Anshuman Khandual <anshuman.khandual@....com>
> +Description: (Read) Shows the TRBE write pointer alignment. This value
> + is fetched from the TRBIDR register.
> +
> +What: /sys/bus/coresight/devices/trbe<cpu>/flag
> +Date: March 2021
> +KernelVersion: 5.13
> +Contact: Anshuman Khandual <anshuman.khandual@....com>
> +Description: (Read) Shows if TRBE updates in the memory are with access
> + and dirty flag updates as well. This value is fetched from
> + the TRBIDR register.
For this file:
Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> diff --git a/Documentation/trace/coresight/coresight-trbe.rst b/Documentation/trace/coresight/coresight-trbe.rst
> new file mode 100644
> index 000000000000..b9928ef148da
> --- /dev/null
> +++ b/Documentation/trace/coresight/coresight-trbe.rst
> @@ -0,0 +1,38 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +==============================
> +Trace Buffer Extension (TRBE).
> +==============================
> +
> + :Author: Anshuman Khandual <anshuman.khandual@....com>
> + :Date: November 2020
> +
> +Hardware Description
> +--------------------
> +
> +Trace Buffer Extension (TRBE) is a percpu hardware which captures in system
> +memory, CPU traces generated from a corresponding percpu tracing unit. This
> +gets plugged in as a coresight sink device because the corresponding trace
> +generators (ETE), are plugged in as source device.
> +
> +The TRBE is not compliant to CoreSight architecture specifications, but is
> +driven via the CoreSight driver framework to support the ETE (which is
> +CoreSight compliant) integration.
> +
> +Sysfs files and directories
> +---------------------------
> +
> +The TRBE devices appear on the existing coresight bus alongside the other
> +coresight devices::
> +
> + >$ ls /sys/bus/coresight/devices
> + trbe0 trbe1 trbe2 trbe3
> +
> +The ``trbe<N>`` named TRBEs are associated with a CPU.::
> +
> + >$ ls /sys/bus/coresight/devices/trbe0/
> + align flag
> +
> +*Key file items are:-*
> + * ``align``: TRBE write pointer alignment
> + * ``flag``: TRBE updates memory with access and dirty flags
For this file:
Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> index f154ae7e705d..84530fd80998 100644
> --- a/drivers/hwtracing/coresight/Kconfig
> +++ b/drivers/hwtracing/coresight/Kconfig
> @@ -173,4 +173,18 @@ config CORESIGHT_CTI_INTEGRATION_REGS
> CTI trigger connections between this and other devices.These
> registers are not used in normal operation and can leave devices in
> an inconsistent state.
> +
> +config CORESIGHT_TRBE
> + tristate "Trace Buffer Extension (TRBE) driver"
> + depends on ARM64 && CORESIGHT_SOURCE_ETM4X
> + help
> + This driver provides support for percpu Trace Buffer Extension (TRBE).
> + TRBE always needs to be used along with it's corresponding percpu ETE
> + component. ETE generates trace data which is then captured with TRBE.
> + Unlike traditional sink devices, TRBE is a CPU feature accessible via
> + system registers. But it's explicit dependency with trace unit (ETE)
> + requires it to be plugged in as a coresight sink device.
> +
> + To compile this driver as a module, choose M here: the module will be
> + called coresight-trbe.
> endif
> diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
> index f20e357758d1..d60816509755 100644
> --- a/drivers/hwtracing/coresight/Makefile
> +++ b/drivers/hwtracing/coresight/Makefile
> @@ -21,5 +21,6 @@ obj-$(CONFIG_CORESIGHT_STM) += coresight-stm.o
> obj-$(CONFIG_CORESIGHT_CPU_DEBUG) += coresight-cpu-debug.o
> obj-$(CONFIG_CORESIGHT_CATU) += coresight-catu.o
> obj-$(CONFIG_CORESIGHT_CTI) += coresight-cti.o
> +obj-$(CONFIG_CORESIGHT_TRBE) += coresight-trbe.o
> coresight-cti-y := coresight-cti-core.o coresight-cti-platform.o \
> coresight-cti-sysfs.o
> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
> new file mode 100644
> index 000000000000..41a012b525bb
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> @@ -0,0 +1,1149 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * This driver enables Trace Buffer Extension (TRBE) as a per-cpu coresight
> + * sink device could then pair with an appropriate per-cpu coresight source
> + * device (ETE) thus generating required trace data. Trace can be enabled
> + * via the perf framework.
If I remember correctly the last version stated the driver was tailored on
Will's SPE driver.
> + *
> + * Copyright (C) 2020 ARM Ltd.
> + *
> + * Author: Anshuman Khandual <anshuman.khandual@....com>
> + */
> +#define DRVNAME "arm_trbe"
> +
> +#define pr_fmt(fmt) DRVNAME ": " fmt
> +
> +#include <asm/barrier.h>
> +#include "coresight-trbe.h"
> +
> +#define PERF_IDX2OFF(idx, buf) ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
> +
> +/*
> + * A padding packet that will help the user space tools
> + * in skipping relevant sections in the captured trace
> + * data which could not be decoded. TRBE doesn't support
> + * formatting the trace data, unlike the legacy CoreSight
> + * sinks and thus we use ETE trace packets to pad the
> + * sections of the buffer.
> + */
> +#define ETE_IGNORE_PACKET 0x70
> +
> +/*
> + * Minimum amount of meaningful trace will contain:
> + * A-Sync, Trace Info, Trace On, Address, Atom.
> + * This is about 44bytes of ETE trace. To be on
> + * the safer side, we assume 64bytes is the minimum
> + * space required for a meaningful session, before
> + * we hit a "WRAP" event.
> + */
> +#define TRBE_TRACE_MIN_BUF_SIZE 64
> +
> +enum trbe_fault_action {
> + TRBE_FAULT_ACT_WRAP,
> + TRBE_FAULT_ACT_SPURIOUS,
> + TRBE_FAULT_ACT_FATAL,
> +};
> +
> +struct trbe_buf {
> + /*
> + * Even though trbe_base represents vmap()
> + * mapped allocated buffer's start address,
> + * it's being as unsigned long for various
> + * arithmetic and comparision operations &
> + * also to be consistent with trbe_write &
> + * trbe_limit sibling pointers.
> + */
> + unsigned long trbe_base;
> + unsigned long trbe_limit;
> + unsigned long trbe_write;
> + int nr_pages;
> + void **pages;
> + bool snapshot;
> + struct trbe_cpudata *cpudata;
> +};
> +
> +struct trbe_cpudata {
> + bool trbe_flag;
> + u64 trbe_align;
> + int cpu;
> + enum cs_mode mode;
> + struct trbe_buf *buf;
> + struct trbe_drvdata *drvdata;
> +};
> +
> +struct trbe_drvdata {
> + struct trbe_cpudata __percpu *cpudata;
> + struct perf_output_handle __percpu **handle;
> + struct hlist_node hotplug_node;
> + int irq;
> + cpumask_t supported_cpus;
> + enum cpuhp_state trbe_online;
> + struct platform_device *pdev;
> +};
> +
> +static int trbe_alloc_node(struct perf_event *event)
> +{
> + if (event->cpu == -1)
> + return NUMA_NO_NODE;
> + return cpu_to_node(event->cpu);
> +}
> +
> +static void trbe_drain_buffer(void)
> +{
> + tsb_csync();
> + dsb(nsh);
> +}
> +
> +static void trbe_drain_and_disable_local(void)
> +{
> + u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
> +
> + trbe_drain_buffer();
> +
> + /*
> + * Disable the TRBE without clearing LIMITPTR which
> + * might be required for fetching the buffer limits.
> + */
> + trblimitr &= ~TRBLIMITR_ENABLE;
> + write_sysreg_s(trblimitr, SYS_TRBLIMITR_EL1);
> + isb();
> +}
> +
> +static void trbe_reset_local(void)
> +{
> + trbe_drain_and_disable_local();
> + write_sysreg_s(0, SYS_TRBLIMITR_EL1);
> + write_sysreg_s(0, SYS_TRBPTR_EL1);
> + write_sysreg_s(0, SYS_TRBBASER_EL1);
> + write_sysreg_s(0, SYS_TRBSR_EL1);
> +}
> +
> +static void trbe_stop_and_truncate_event(struct perf_output_handle *handle)
> +{
> + struct trbe_buf *buf = etm_perf_sink_config(handle);
> +
> + /*
> + * We cannot proceed with the buffer collection and we
> + * do not have any data for the current session. The
> + * etm_perf driver expects to close out the aux_buffer
> + * at event_stop(). So disable the TRBE here and leave
> + * the update_buffer() to return a 0 size.
> + */
> + trbe_drain_and_disable_local();
> + perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
> + *this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL;
> +}
> +
> +/*
> + * TRBE Buffer Management
> + *
> + * The TRBE buffer spans from the base pointer till the limit pointer. When enabled,
> + * it starts writing trace data from the write pointer onward till the limit pointer.
> + * When the write pointer reaches the address just before the limit pointer, it gets
> + * wrapped around again to the base pointer. This is called a TRBE wrap event, which
> + * generates a maintenance interrupt when operated in WRAP or FILL mode. This driver
> + * uses FILL mode, where the TRBE stops the trace collection at wrap event. The IRQ
> + * handler updates the AUX buffer and re-enables the TRBE with updated WRITE and
> + * LIMIT pointers.
> + *
> + * Wrap around with an IRQ
> + * ------ < ------ < ------- < ----- < -----
> + * | |
> + * ------ > ------ > ------- > ----- > -----
> + *
> + * +---------------+-----------------------+
> + * | | |
> + * +---------------+-----------------------+
> + * Base Pointer Write Pointer Limit Pointer
> + *
> + * The base and limit pointers always needs to be PAGE_SIZE aligned. But the write
> + * pointer can be aligned to the implementation defined TRBE trace buffer alignment
> + * as captured in trbe_cpudata->trbe_align.
> + *
> + *
> + * head tail wakeup
> + * +---------------------------------------+----- ~ ~ ------
> + * |$$$$$$$|################|$$$$$$$$$$$$$$| |
> + * +---------------------------------------+----- ~ ~ ------
> + * Base Pointer Write Pointer Limit Pointer
> + *
> + * The perf_output_handle indices (head, tail, wakeup) are monotonically increasing
> + * values which tracks all the driver writes and user reads from the perf auxiliary
> + * buffer. Generally [head..tail] is the area where the driver can write into unless
> + * the wakeup is behind the tail. Enabled TRBE buffer span needs to be adjusted and
> + * configured depending on the perf_output_handle indices, so that the driver does
> + * not override into areas in the perf auxiliary buffer which is being or yet to be
> + * consumed from the user space. The enabled TRBE buffer area is a moving subset of
> + * the allocated perf auxiliary buffer.
> + */
> +static void trbe_pad_buf(struct perf_output_handle *handle, int len)
> +{
> + struct trbe_buf *buf = etm_perf_sink_config(handle);
> + u64 head = PERF_IDX2OFF(handle->head, buf);
> +
> + memset((void *)buf->trbe_base + head, ETE_IGNORE_PACKET, len);
> + if (!buf->snapshot)
> + perf_aux_output_skip(handle, len);
> +}
> +
> +static unsigned long trbe_snapshot_offset(struct perf_output_handle *handle)
> +{
> + struct trbe_buf *buf = etm_perf_sink_config(handle);
> +
> + /*
> + * The ETE trace has alignment synchronization packets allowing
> + * the decoder to reset in case of an overflow or corruption.
> + * So we can use the entire buffer for the snapshot mode.
> + */
> + return buf->nr_pages * PAGE_SIZE;
> +}
> +
> +/*
> + * TRBE Limit Calculation
> + *
> + * The following markers are used to illustrate various TRBE buffer situations.
> + *
> + * $$$$ - Data area, unconsumed captured trace data, not to be overridden
> + * #### - Free area, enabled, trace will be written
> + * %%%% - Free area, disabled, trace will not be written
> + * ==== - Free area, padded with ETE_IGNORE_PACKET, trace will be skipped
> + */
> +static unsigned long __trbe_normal_offset(struct perf_output_handle *handle)
> +{
> + struct trbe_buf *buf = etm_perf_sink_config(handle);
> + struct trbe_cpudata *cpudata = buf->cpudata;
> + const u64 bufsize = buf->nr_pages * PAGE_SIZE;
> + u64 limit = bufsize;
> + u64 head, tail, wakeup;
> +
> + head = PERF_IDX2OFF(handle->head, buf);
> +
> + /*
> + * head
> + * ------->|
> + * |
> + * head TRBE align tail
> + * +----|-------|---------------|-------+
> + * |$$$$|=======|###############|$$$$$$$|
> + * +----|-------|---------------|-------+
> + * trbe_base trbe_base + nr_pages
> + *
> + * Perf aux buffer output head position can be misaligned depending on
> + * various factors including user space reads. In case misaligned, head
> + * needs to be aligned before TRBE can be configured. Pad the alignment
> + * gap with ETE_IGNORE_PACKET bytes that will be ignored by user tools
> + * and skip this section thus advancing the head.
> + */
> + if (!IS_ALIGNED(head, cpudata->trbe_align)) {
> + unsigned long delta = roundup(head, cpudata->trbe_align) - head;
> +
> + delta = min(delta, handle->size);
> + trbe_pad_buf(handle, delta);
> + head = PERF_IDX2OFF(handle->head, buf);
> + }
> +
> + /*
> + * head = tail (size = 0)
> + * +----|-------------------------------+
> + * |$$$$|$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ |
> + * +----|-------------------------------+
> + * trbe_base trbe_base + nr_pages
> + *
> + * Perf aux buffer does not have any space for the driver to write into.
> + * Just communicate trace truncation event to the user space by marking
> + * it with PERF_AUX_FLAG_TRUNCATED.
> + */
> + if (!handle->size) {
> + perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
> + return 0;
> + }
> +
> + /* Compute the tail and wakeup indices now that we've aligned head */
> + tail = PERF_IDX2OFF(handle->head + handle->size, buf);
> + wakeup = PERF_IDX2OFF(handle->wakeup, buf);
> +
> + /*
> + * Lets calculate the buffer area which TRBE could write into. There
> + * are three possible scenarios here. Limit needs to be aligned with
> + * PAGE_SIZE per the TRBE requirement. Always avoid clobbering the
> + * unconsumed data.
> + *
> + * 1) head < tail
> + *
> + * head tail
> + * +----|-----------------------|-------+
> + * |$$$$|#######################|$$$$$$$|
> + * +----|-----------------------|-------+
> + * trbe_base limit trbe_base + nr_pages
> + *
> + * TRBE could write into [head..tail] area. Unless the tail is right at
> + * the end of the buffer, neither an wrap around nor an IRQ is expected
> + * while being enabled.
> + *
> + * 2) head == tail
> + *
> + * head = tail (size > 0)
> + * +----|-------------------------------+
> + * |%%%%|###############################|
> + * +----|-------------------------------+
> + * trbe_base limit = trbe_base + nr_pages
> + *
> + * TRBE should just write into [head..base + nr_pages] area even though
> + * the entire buffer is empty. Reason being, when the trace reaches the
> + * end of the buffer, it will just wrap around with an IRQ giving an
> + * opportunity to reconfigure the buffer.
> + *
> + * 3) tail < head
> + *
> + * tail head
> + * +----|-----------------------|-------+
> + * |%%%%|$$$$$$$$$$$$$$$$$$$$$$$|#######|
> + * +----|-----------------------|-------+
> + * trbe_base limit = trbe_base + nr_pages
> + *
> + * TRBE should just write into [head..base + nr_pages] area even though
> + * the [trbe_base..tail] is also empty. Reason being, when the trace
> + * reaches the end of the buffer, it will just wrap around with an IRQ
> + * giving an opportunity to reconfigure the buffer.
> + */
> + if (head < tail)
> + limit = round_down(tail, PAGE_SIZE);
> +
> + /*
> + * Wakeup may be arbitrarily far into the future. If it's not in the
> + * current generation, either we'll wrap before hitting it, or it's
> + * in the past and has been handled already.
> + *
> + * If there's a wakeup before we wrap, arrange to be woken up by the
> + * page boundary following it. Keep the tail boundary if that's lower.
> + *
> + * head wakeup tail
> + * +----|---------------|-------|-------+
> + * |$$$$|###############|%%%%%%%|$$$$$$$|
> + * +----|---------------|-------|-------+
> + * trbe_base limit trbe_base + nr_pages
> + */
> + if (handle->wakeup < (handle->head + handle->size) && head <= wakeup)
> + limit = min(limit, round_up(wakeup, PAGE_SIZE));
> +
> + /*
> + * There are two situation when this can happen i.e limit is before
> + * the head and hence TRBE cannot be configured.
> + *
> + * 1) head < tail (aligned down with PAGE_SIZE) and also they are both
> + * within the same PAGE size range.
> + *
> + * PAGE_SIZE
> + * |----------------------|
> + *
> + * limit head tail
> + * +------------|------|--------|-------+
> + * |$$$$$$$$$$$$$$$$$$$|========|$$$$$$$|
> + * +------------|------|--------|-------+
> + * trbe_base trbe_base + nr_pages
> + *
> + * 2) head < wakeup (aligned up with PAGE_SIZE) < tail and also both
> + * head and wakeup are within same PAGE size range.
> + *
> + * PAGE_SIZE
> + * |----------------------|
> + *
> + * limit head wakeup tail
> + * +----|------|-------|--------|-------+
> + * |$$$$$$$$$$$|=======|========|$$$$$$$|
> + * +----|------|-------|--------|-------+
> + * trbe_base trbe_base + nr_pages
> + */
> + if (limit > head)
> + return limit;
> +
> + trbe_pad_buf(handle, handle->size);
> + perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
> + return 0;
> +}
> +
> +static unsigned long trbe_normal_offset(struct perf_output_handle *handle)
> +{
> + struct trbe_buf *buf = perf_get_aux(handle);
> + u64 limit = __trbe_normal_offset(handle);
> + u64 head = PERF_IDX2OFF(handle->head, buf);
> +
> + /*
> + * If the head is too close to the limit and we don't
> + * have space for a meaningful run, we rather pad it
> + * and start fresh.
> + */
> + if (limit && (limit - head < TRBE_TRACE_MIN_BUF_SIZE)) {
> + trbe_pad_buf(handle, limit - head);
> + limit = __trbe_normal_offset(handle);
> + }
> + return limit;
> +}
> +
> +static unsigned long compute_trbe_buffer_limit(struct perf_output_handle *handle)
> +{
> + struct trbe_buf *buf = etm_perf_sink_config(handle);
> + unsigned long offset;
> +
> + if (buf->snapshot)
> + offset = trbe_snapshot_offset(handle);
> + else
> + offset = trbe_normal_offset(handle);
> + return buf->trbe_base + offset;
> +}
> +
> +static void clr_trbe_status(void)
> +{
> + u64 trbsr = read_sysreg_s(SYS_TRBSR_EL1);
> +
> + WARN_ON(is_trbe_enabled());
> + trbsr &= ~TRBSR_IRQ;
> + trbsr &= ~TRBSR_TRG;
> + trbsr &= ~TRBSR_WRAP;
> + trbsr &= ~(TRBSR_EC_MASK << TRBSR_EC_SHIFT);
> + trbsr &= ~(TRBSR_BSC_MASK << TRBSR_BSC_SHIFT);
> + trbsr &= ~TRBSR_STOP;
> + write_sysreg_s(trbsr, SYS_TRBSR_EL1);
> +}
> +
> +static void set_trbe_limit_pointer_enabled(unsigned long addr)
> +{
> + u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
> +
> + WARN_ON(!IS_ALIGNED(addr, (1UL << TRBLIMITR_LIMIT_SHIFT)));
> + WARN_ON(!IS_ALIGNED(addr, PAGE_SIZE));
> +
> + trblimitr &= ~TRBLIMITR_NVM;
> + trblimitr &= ~(TRBLIMITR_FILL_MODE_MASK << TRBLIMITR_FILL_MODE_SHIFT);
> + trblimitr &= ~(TRBLIMITR_TRIG_MODE_MASK << TRBLIMITR_TRIG_MODE_SHIFT);
> + trblimitr &= ~(TRBLIMITR_LIMIT_MASK << TRBLIMITR_LIMIT_SHIFT);
> +
> + /*
> + * Fill trace buffer mode is used here while configuring the
> + * TRBE for trace capture. In this particular mode, the trace
> + * collection is stopped and a maintenance interrupt is raised
> + * when the current write pointer wraps. This pause in trace
> + * collection gives the software an opportunity to capture the
> + * trace data in the interrupt handler, before reconfiguring
> + * the TRBE.
> + */
> + trblimitr |= (TRBE_FILL_MODE_FILL & TRBLIMITR_FILL_MODE_MASK) << TRBLIMITR_FILL_MODE_SHIFT;
> +
> + /*
> + * Trigger mode is not used here while configuring the TRBE for
> + * the trace capture. Hence just keep this in the ignore mode.
> + */
> + trblimitr |= (TRBE_TRIG_MODE_IGNORE & TRBLIMITR_TRIG_MODE_MASK) <<
> + TRBLIMITR_TRIG_MODE_SHIFT;
> + trblimitr |= (addr & PAGE_MASK);
> +
> + trblimitr |= TRBLIMITR_ENABLE;
> + write_sysreg_s(trblimitr, SYS_TRBLIMITR_EL1);
> +
> + /* Synchronize the TRBE enable event */
> + isb();
> +}
> +
> +static void trbe_enable_hw(struct trbe_buf *buf)
> +{
> + WARN_ON(buf->trbe_write < buf->trbe_base);
> + WARN_ON(buf->trbe_write >= buf->trbe_limit);
> + set_trbe_disabled();
> + isb();
> + clr_trbe_status();
> + set_trbe_base_pointer(buf->trbe_base);
> + set_trbe_write_pointer(buf->trbe_write);
> +
> + /*
> + * Synchronize all the register updates
> + * till now before enabling the TRBE.
> + */
> + isb();
> + set_trbe_limit_pointer_enabled(buf->trbe_limit);
> +}
> +
> +static enum trbe_fault_action trbe_get_fault_act(u64 trbsr)
> +{
> + int ec = get_trbe_ec(trbsr);
> + int bsc = get_trbe_bsc(trbsr);
> +
> + WARN_ON(is_trbe_running(trbsr));
> + if (is_trbe_trg(trbsr) || is_trbe_abort(trbsr))
> + return TRBE_FAULT_ACT_FATAL;
> +
> + if ((ec == TRBE_EC_STAGE1_ABORT) || (ec == TRBE_EC_STAGE2_ABORT))
> + return TRBE_FAULT_ACT_FATAL;
> +
> + if (is_trbe_wrap(trbsr) && (ec == TRBE_EC_OTHERS) && (bsc == TRBE_BSC_FILLED)) {
> + if (get_trbe_write_pointer() == get_trbe_base_pointer())
> + return TRBE_FAULT_ACT_WRAP;
> + }
> + return TRBE_FAULT_ACT_SPURIOUS;
> +}
> +
> +static void *arm_trbe_alloc_buffer(struct coresight_device *csdev,
> + struct perf_event *event, void **pages,
> + int nr_pages, bool snapshot)
> +{
> + struct trbe_buf *buf;
> + struct page **pglist;
> + int i;
> +
> + /*
> + * TRBE LIMIT and TRBE WRITE pointers must be page aligned. But with
> + * just a single page, there would not be any room left while writing
> + * into a partially filled TRBE buffer after the page size alignment.
> + * Hence restrict the minimum buffer size as two pages.
> + */
> + if (nr_pages < 2)
> + return NULL;
> +
> + buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, trbe_alloc_node(event));
> + if (!buf)
> + return ERR_PTR(-ENOMEM);
> +
> + pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
> + if (!pglist) {
> + kfree(buf);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + for (i = 0; i < nr_pages; i++)
> + pglist[i] = virt_to_page(pages[i]);
> +
> + buf->trbe_base = (unsigned long)vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL);
> + if (!buf->trbe_base) {
> + kfree(pglist);
> + kfree(buf);
> + return ERR_PTR(buf->trbe_base);
> + }
> + buf->trbe_limit = buf->trbe_base + nr_pages * PAGE_SIZE;
> + buf->trbe_write = buf->trbe_base;
> + buf->snapshot = snapshot;
> + buf->nr_pages = nr_pages;
> + buf->pages = pages;
> + kfree(pglist);
> + return buf;
> +}
> +
> +static void arm_trbe_free_buffer(void *config)
> +{
> + struct trbe_buf *buf = config;
> +
> + vunmap((void *)buf->trbe_base);
> + kfree(buf);
> +}
> +
> +static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev,
> + struct perf_output_handle *handle,
> + void *config)
> +{
> + struct trbe_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> + struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev);
> + struct trbe_buf *buf = config;
> + enum trbe_fault_action act;
> + unsigned long size, offset;
> + unsigned long write, base, status;
> + unsigned long flags;
> +
> + WARN_ON(buf->cpudata != cpudata);
> + WARN_ON(cpudata->cpu != smp_processor_id());
> + WARN_ON(cpudata->drvdata != drvdata);
> + if (cpudata->mode != CS_MODE_PERF)
> + return 0;
> +
> + perf_aux_output_flag(handle, PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW);
> +
> + /*
> + * We are about to disable the TRBE. And this could in turn
> + * fill up the buffer triggering, an IRQ. This could be consumed
> + * by the PE asynchronously, causing a race here against
> + * the IRQ handler in closing out the handle. So, let us
> + * make sure the IRQ can't trigger while we are collecting
> + * the buffer. We also make sure that a WRAP event is handled
> + * accordingly.
> + */
> + local_irq_save(flags);
> +
> + /*
> + * If the TRBE was disabled due to lack of space in the AUX buffer or a
> + * spurious fault, the driver leaves it disabled, truncating the buffer.
> + * Since the etm_perf driver expects to close out the AUX buffer, the
> + * driver skips it. Thus, just pass in 0 size here to indicate that the
> + * buffer was truncated.
> + */
> + if (!is_trbe_enabled()) {
> + size = 0;
> + goto done;
> + }
> + /*
> + * perf handle structure needs to be shared with the TRBE IRQ handler for
> + * capturing trace data and restarting the handle. There is a probability
> + * of an undefined reference based crash when etm event is being stopped
> + * while a TRBE IRQ also getting processed. This happens due the release
> + * of perf handle via perf_aux_output_end() in etm_event_stop(). Stopping
> + * the TRBE here will ensure that no IRQ could be generated when the perf
> + * handle gets freed in etm_event_stop().
> + */
> + trbe_drain_and_disable_local();
> + write = get_trbe_write_pointer();
> + base = get_trbe_base_pointer();
> +
> + /* Check if there is a pending interrupt and handle it here */
> + status = read_sysreg_s(SYS_TRBSR_EL1);
> + if (is_trbe_irq(status)) {
> +
> + /*
> + * Now that we are handling the IRQ here, clear the IRQ
> + * from the status, to let the irq handler know that it
> + * is taken care of.
> + */
> + clr_trbe_irq();
> + isb();
> +
> + act = trbe_get_fault_act(status);
> + /*
> + * If this was not due to a WRAP event, we have some
> + * errors and as such buffer is empty.
> + */
> + if (act != TRBE_FAULT_ACT_WRAP) {
> + size = 0;
> + goto done;
> + }
> +
> + /*
> + * Otherwise, the buffer is full and the write pointer
> + * has reached base. Adjust this back to the Limit pointer
> + * for correct size.
> + */
> + write = get_trbe_limit_pointer();
> + }
> +
> + offset = write - base;
> + if (WARN_ON_ONCE(offset < PERF_IDX2OFF(handle->head, buf)))
> + size = 0;
> + else
> + size = offset - PERF_IDX2OFF(handle->head, buf);
> +
> +done:
> + local_irq_restore(flags);
> +
> + if (buf->snapshot)
> + handle->head += size;
> + return size;
> +}
> +
> +static int arm_trbe_enable(struct coresight_device *csdev, u32 mode, void *data)
> +{
> + struct trbe_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> + struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev);
> + struct perf_output_handle *handle = data;
> + struct trbe_buf *buf = etm_perf_sink_config(handle);
> +
> + WARN_ON(cpudata->cpu != smp_processor_id());
> + WARN_ON(cpudata->drvdata != drvdata);
> + if (mode != CS_MODE_PERF)
> + return -EINVAL;
> +
> + *this_cpu_ptr(drvdata->handle) = handle;
> + cpudata->buf = buf;
> + cpudata->mode = mode;
> + buf->cpudata = cpudata;
> + buf->trbe_limit = compute_trbe_buffer_limit(handle);
> + buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf);
> + if (buf->trbe_limit == buf->trbe_base) {
> + trbe_stop_and_truncate_event(handle);
> + return 0;
> + }
> + trbe_enable_hw(buf);
> + return 0;
> +}
> +
> +static int arm_trbe_disable(struct coresight_device *csdev)
> +{
> + struct trbe_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> + struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev);
> + struct trbe_buf *buf = cpudata->buf;
> +
> + WARN_ON(buf->cpudata != cpudata);
> + WARN_ON(cpudata->cpu != smp_processor_id());
> + WARN_ON(cpudata->drvdata != drvdata);
> + if (cpudata->mode != CS_MODE_PERF)
> + return -EINVAL;
> +
> + trbe_drain_and_disable_local();
> + buf->cpudata = NULL;
> + cpudata->buf = NULL;
> + cpudata->mode = CS_MODE_DISABLED;
> + return 0;
> +}
> +
> +static void trbe_handle_spurious(struct perf_output_handle *handle)
> +{
> + struct trbe_buf *buf = etm_perf_sink_config(handle);
> +
> + buf->trbe_limit = compute_trbe_buffer_limit(handle);
> + buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf);
> + if (buf->trbe_limit == buf->trbe_base) {
> + trbe_drain_and_disable_local();
> + return;
> + }
> + trbe_enable_hw(buf);
> +}
> +
> +static void trbe_handle_overflow(struct perf_output_handle *handle)
> +{
> + struct perf_event *event = handle->event;
> + struct trbe_buf *buf = etm_perf_sink_config(handle);
> + unsigned long offset, size;
> + struct etm_event_data *event_data;
> +
> + offset = get_trbe_limit_pointer() - get_trbe_base_pointer();
> + size = offset - PERF_IDX2OFF(handle->head, buf);
> + if (buf->snapshot)
> + handle->head += size;
> +
> + perf_aux_output_flag(handle, PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW);
> + perf_aux_output_end(handle, size);
> + event_data = perf_aux_output_begin(handle, event);
> + if (!event_data) {
> + /*
> + * We are unable to restart the trace collection,
> + * thus leave the TRBE disabled. The etm-perf driver
> + * is able to detect this with a disconnected handle
> + * (handle->event = NULL).
> + */
> + trbe_drain_and_disable_local();
> + *this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL;
> + return;
> + }
> + buf->trbe_limit = compute_trbe_buffer_limit(handle);
> + buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf);
> + if (buf->trbe_limit == buf->trbe_base) {
> + trbe_stop_and_truncate_event(handle);
> + return;
> + }
> + *this_cpu_ptr(buf->cpudata->drvdata->handle) = handle;
> + trbe_enable_hw(buf);
> +}
> +
> +static bool is_perf_trbe(struct perf_output_handle *handle)
> +{
> + struct trbe_buf *buf = etm_perf_sink_config(handle);
> + struct trbe_cpudata *cpudata = buf->cpudata;
> + struct trbe_drvdata *drvdata = cpudata->drvdata;
> + int cpu = smp_processor_id();
> +
> + WARN_ON(buf->trbe_base != get_trbe_base_pointer());
> + WARN_ON(buf->trbe_limit != get_trbe_limit_pointer());
> +
> + if (cpudata->mode != CS_MODE_PERF)
> + return false;
> +
> + if (cpudata->cpu != cpu)
> + return false;
> +
> + if (!cpumask_test_cpu(cpu, &drvdata->supported_cpus))
> + return false;
> +
> + return true;
> +}
> +
> +static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
> +{
> + struct perf_output_handle **handle_ptr = dev;
> + struct perf_output_handle *handle = *handle_ptr;
> + enum trbe_fault_action act;
> + u64 status;
> +
> + /*
> + * Ensure the trace is visible to the CPUs and
> + * any external aborts have been resolved.
> + */
> + trbe_drain_and_disable_local();
> +
> + status = read_sysreg_s(SYS_TRBSR_EL1);
> + /*
> + * If the pending IRQ was handled by update_buffer callback
> + * we have nothing to do here.
> + */
> + if (!is_trbe_irq(status))
> + return IRQ_NONE;
> +
> + clr_trbe_irq();
> + isb();
> +
> + if (WARN_ON_ONCE(!handle) || !perf_get_aux(handle))
> + return IRQ_NONE;
> +
> + if (!is_perf_trbe(handle))
> + return IRQ_NONE;
> +
> + /*
> + * Ensure perf callbacks have completed, which may disable
> + * the trace buffer in response to a TRUNCATION flag.
> + */
> + irq_work_run();
> +
> + act = trbe_get_fault_act(status);
> + switch (act) {
> + case TRBE_FAULT_ACT_WRAP:
> + trbe_handle_overflow(handle);
> + break;
> + case TRBE_FAULT_ACT_SPURIOUS:
> + trbe_handle_spurious(handle);
> + break;
> + case TRBE_FAULT_ACT_FATAL:
> + trbe_stop_and_truncate_event(handle);
> + break;
> + }
> + return IRQ_HANDLED;
> +}
> +
> +static const struct coresight_ops_sink arm_trbe_sink_ops = {
> + .enable = arm_trbe_enable,
> + .disable = arm_trbe_disable,
> + .alloc_buffer = arm_trbe_alloc_buffer,
> + .free_buffer = arm_trbe_free_buffer,
> + .update_buffer = arm_trbe_update_buffer,
> +};
> +
> +static const struct coresight_ops arm_trbe_cs_ops = {
> + .sink_ops = &arm_trbe_sink_ops,
> +};
> +
> +static ssize_t align_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> + struct trbe_cpudata *cpudata = dev_get_drvdata(dev);
> +
> + return sprintf(buf, "%llx\n", cpudata->trbe_align);
> +}
> +static DEVICE_ATTR_RO(align);
> +
> +static ssize_t flag_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> + struct trbe_cpudata *cpudata = dev_get_drvdata(dev);
> +
> + return sprintf(buf, "%d\n", cpudata->trbe_flag);
> +}
> +static DEVICE_ATTR_RO(flag);
> +
> +static struct attribute *arm_trbe_attrs[] = {
> + &dev_attr_align.attr,
> + &dev_attr_flag.attr,
> + NULL,
> +};
> +
> +static const struct attribute_group arm_trbe_group = {
> + .attrs = arm_trbe_attrs,
> +};
> +
> +static const struct attribute_group *arm_trbe_groups[] = {
> + &arm_trbe_group,
> + NULL,
> +};
> +
> +static void arm_trbe_enable_cpu(void *info)
> +{
> + struct trbe_drvdata *drvdata = info;
> +
> + trbe_reset_local();
> + enable_percpu_irq(drvdata->irq, IRQ_TYPE_NONE);
> +}
> +
> +static void arm_trbe_register_coresight_cpu(struct trbe_drvdata *drvdata, int cpu)
> +{
> + struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
> + struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu);
> + struct coresight_desc desc = { 0 };
> + struct device *dev;
> +
> + if (WARN_ON(trbe_csdev))
> + return;
> +
> + dev = &cpudata->drvdata->pdev->dev;
> + desc.name = devm_kasprintf(dev, GFP_KERNEL, "trbe%d", cpu);
> + if (IS_ERR(desc.name))
> + goto cpu_clear;
> +
> + desc.type = CORESIGHT_DEV_TYPE_SINK;
> + desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM;
> + desc.ops = &arm_trbe_cs_ops;
> + desc.pdata = dev_get_platdata(dev);
> + desc.groups = arm_trbe_groups;
> + desc.dev = dev;
> + trbe_csdev = coresight_register(&desc);
> + if (IS_ERR(trbe_csdev))
> + goto cpu_clear;
> +
> + dev_set_drvdata(&trbe_csdev->dev, cpudata);
> + coresight_set_percpu_sink(cpu, trbe_csdev);
> + return;
> +cpu_clear:
> + cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
> +}
> +
> +static void arm_trbe_probe_cpu(void *info)
> +{
> + struct trbe_drvdata *drvdata = info;
> + int cpu = smp_processor_id();
> + struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
> + u64 trbidr;
> +
> + if (WARN_ON(!cpudata))
> + goto cpu_clear;
> +
> + if (!is_trbe_available()) {
> + pr_err("TRBE is not implemented on cpu %d\n", cpu);
> + goto cpu_clear;
> + }
> +
> + trbidr = read_sysreg_s(SYS_TRBIDR_EL1);
> + if (!is_trbe_programmable(trbidr)) {
> + pr_err("TRBE is owned in higher exception level on cpu %d\n", cpu);
> + goto cpu_clear;
> + }
> +
> + cpudata->trbe_align = 1ULL << get_trbe_address_align(trbidr);
> + if (cpudata->trbe_align > SZ_2K) {
> + pr_err("Unsupported alignment on cpu %d\n", cpu);
> + goto cpu_clear;
> + }
> + cpudata->trbe_flag = get_trbe_flag_update(trbidr);
> + cpudata->cpu = cpu;
> + cpudata->drvdata = drvdata;
> + return;
> +cpu_clear:
> + cpumask_clear_cpu(cpu, &drvdata->supported_cpus);
> +}
> +
> +static void arm_trbe_remove_coresight_cpu(void *info)
> +{
> + int cpu = smp_processor_id();
> + struct trbe_drvdata *drvdata = info;
> + struct trbe_cpudata *cpudata = per_cpu_ptr(drvdata->cpudata, cpu);
> + struct coresight_device *trbe_csdev = coresight_get_percpu_sink(cpu);
> +
> + disable_percpu_irq(drvdata->irq);
> + trbe_reset_local();
> + if (trbe_csdev) {
> + coresight_unregister(trbe_csdev);
> + cpudata->drvdata = NULL;
> + coresight_set_percpu_sink(cpu, NULL);
> + }
> +}
> +
> +static int arm_trbe_probe_coresight(struct trbe_drvdata *drvdata)
> +{
> + int cpu;
> +
> + drvdata->cpudata = alloc_percpu(typeof(*drvdata->cpudata));
> + if (!drvdata->cpudata)
> + return -ENOMEM;
> +
> + for_each_cpu(cpu, &drvdata->supported_cpus) {
> + smp_call_function_single(cpu, arm_trbe_probe_cpu, drvdata, 1);
> + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
> + arm_trbe_register_coresight_cpu(drvdata, cpu);
> + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
> + smp_call_function_single(cpu, arm_trbe_enable_cpu, drvdata, 1);
> + }
> + return 0;
> +}
> +
> +static int arm_trbe_remove_coresight(struct trbe_drvdata *drvdata)
> +{
> + int cpu;
> +
> + for_each_cpu(cpu, &drvdata->supported_cpus)
> + smp_call_function_single(cpu, arm_trbe_remove_coresight_cpu, drvdata, 1);
> + free_percpu(drvdata->cpudata);
> + return 0;
> +}
> +
> +static int arm_trbe_cpu_startup(unsigned int cpu, struct hlist_node *node)
> +{
> + struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct trbe_drvdata, hotplug_node);
> +
> + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
> +
> + /*
> + * If this CPU was not probed for TRBE,
> + * initialize it now.
> + */
> + if (!coresight_get_percpu_sink(cpu)) {
> + arm_trbe_probe_cpu(drvdata);
> + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
> + arm_trbe_register_coresight_cpu(drvdata, cpu);
> + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus))
> + arm_trbe_enable_cpu(drvdata);
> + } else {
> + arm_trbe_enable_cpu(drvdata);
> + }
> + }
> + return 0;
> +}
> +
> +static int arm_trbe_cpu_teardown(unsigned int cpu, struct hlist_node *node)
> +{
> + struct trbe_drvdata *drvdata = hlist_entry_safe(node, struct trbe_drvdata, hotplug_node);
> +
> + if (cpumask_test_cpu(cpu, &drvdata->supported_cpus)) {
> + disable_percpu_irq(drvdata->irq);
> + trbe_reset_local();
> + }
> + return 0;
> +}
> +
> +static int arm_trbe_probe_cpuhp(struct trbe_drvdata *drvdata)
> +{
> + enum cpuhp_state trbe_online;
> + int ret;
> +
> + trbe_online = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME,
> + arm_trbe_cpu_startup, arm_trbe_cpu_teardown);
> + if (trbe_online < 0)
> + return trbe_online;
> +
> + ret = cpuhp_state_add_instance(trbe_online, &drvdata->hotplug_node);
> + if (ret) {
> + cpuhp_remove_multi_state(trbe_online);
> + return ret;
> + }
> + drvdata->trbe_online = trbe_online;
> + return 0;
> +}
> +
> +static void arm_trbe_remove_cpuhp(struct trbe_drvdata *drvdata)
> +{
> + cpuhp_remove_multi_state(drvdata->trbe_online);
> +}
> +
> +static int arm_trbe_probe_irq(struct platform_device *pdev,
> + struct trbe_drvdata *drvdata)
> +{
> + int ret;
> +
> + drvdata->irq = platform_get_irq(pdev, 0);
> + if (drvdata->irq < 0) {
> + pr_err("IRQ not found for the platform device\n");
> + return drvdata->irq;
> + }
> +
> + if (!irq_is_percpu(drvdata->irq)) {
> + pr_err("IRQ is not a PPI\n");
> + return -EINVAL;
> + }
> +
> + if (irq_get_percpu_devid_partition(drvdata->irq, &drvdata->supported_cpus))
> + return -EINVAL;
> +
> + drvdata->handle = alloc_percpu(typeof(*drvdata->handle));
> + if (!drvdata->handle)
> + return -ENOMEM;
> +
> + ret = request_percpu_irq(drvdata->irq, arm_trbe_irq_handler, DRVNAME, drvdata->handle);
> + if (ret) {
> + free_percpu(drvdata->handle);
> + return ret;
> + }
> + return 0;
> +}
> +
> +static void arm_trbe_remove_irq(struct trbe_drvdata *drvdata)
> +{
> + free_percpu_irq(drvdata->irq, drvdata->handle);
> + free_percpu(drvdata->handle);
> +}
> +
> +static int arm_trbe_device_probe(struct platform_device *pdev)
> +{
> + struct coresight_platform_data *pdata;
> + struct trbe_drvdata *drvdata;
> + struct device *dev = &pdev->dev;
> + int ret;
> +
> + drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
> + if (!drvdata)
> + return -ENOMEM;
> +
> + pdata = coresight_get_platform_data(dev);
> + if (IS_ERR(pdata))
> + return PTR_ERR(pdata);
Given there is no in and out ports, do we need a platform data for this driver?
More comments on this patch tomorrow.
Thanks,
Mathieu
> +
> + dev_set_drvdata(dev, drvdata);
> + dev->platform_data = pdata;
> + drvdata->pdev = pdev;
> + ret = arm_trbe_probe_irq(pdev, drvdata);
> + if (ret)
> + return ret;
> +
> + ret = arm_trbe_probe_coresight(drvdata);
> + if (ret)
> + goto probe_failed;
> +
> + ret = arm_trbe_probe_cpuhp(drvdata);
> + if (ret)
> + goto cpuhp_failed;
> +
> + return 0;
> +cpuhp_failed:
> + arm_trbe_remove_coresight(drvdata);
> +probe_failed:
> + arm_trbe_remove_irq(drvdata);
> + return ret;
> +}
> +
> +static int arm_trbe_device_remove(struct platform_device *pdev)
> +{
> + struct trbe_drvdata *drvdata = platform_get_drvdata(pdev);
> +
> + arm_trbe_remove_cpuhp(drvdata);
> + arm_trbe_remove_coresight(drvdata);
> + arm_trbe_remove_irq(drvdata);
> + return 0;
> +}
> +
> +static const struct of_device_id arm_trbe_of_match[] = {
> + { .compatible = "arm,trace-buffer-extension"},
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, arm_trbe_of_match);
> +
> +static struct platform_driver arm_trbe_driver = {
> + .driver = {
> + .name = DRVNAME,
> + .of_match_table = of_match_ptr(arm_trbe_of_match),
> + .suppress_bind_attrs = true,
> + },
> + .probe = arm_trbe_device_probe,
> + .remove = arm_trbe_device_remove,
> +};
> +
> +static int __init arm_trbe_init(void)
> +{
> + int ret;
> +
> + if (arm64_kernel_unmapped_at_el0()) {
> + pr_err("TRBE wouldn't work if kernel gets unmapped at EL0\n");
> + return -EOPNOTSUPP;
> + }
> +
> + ret = platform_driver_register(&arm_trbe_driver);
> + if (!ret)
> + return 0;
> +
> + pr_err("Error registering %s platform driver\n", DRVNAME);
> + return ret;
> +}
> +
> +static void __exit arm_trbe_exit(void)
> +{
> + platform_driver_unregister(&arm_trbe_driver);
> +}
> +module_init(arm_trbe_init);
> +module_exit(arm_trbe_exit);
> +
> +MODULE_AUTHOR("Anshuman Khandual <anshuman.khandual@....com>");
> +MODULE_DESCRIPTION("Arm Trace Buffer Extension (TRBE) driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/hwtracing/coresight/coresight-trbe.h b/drivers/hwtracing/coresight/coresight-trbe.h
> new file mode 100644
> index 000000000000..499b846ccfee
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/coresight-trbe.h
> @@ -0,0 +1,153 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * This contains all required hardware related helper functions for
> + * Trace Buffer Extension (TRBE) driver in the coresight framework.
> + *
> + * Copyright (C) 2020 ARM Ltd.
> + *
> + * Author: Anshuman Khandual <anshuman.khandual@....com>
> + */
> +#include <linux/coresight.h>
> +#include <linux/device.h>
> +#include <linux/irq.h>
> +#include <linux/kernel.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/smp.h>
> +
> +#include "coresight-etm-perf.h"
> +
> +static inline bool is_trbe_available(void)
> +{
> + u64 aa64dfr0 = read_sysreg_s(SYS_ID_AA64DFR0_EL1);
> + unsigned int trbe = cpuid_feature_extract_unsigned_field(aa64dfr0, ID_AA64DFR0_TRBE_SHIFT);
> +
> + return trbe >= 0b0001;
> +}
> +
> +static inline bool is_trbe_enabled(void)
> +{
> + u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
> +
> + return trblimitr & TRBLIMITR_ENABLE;
> +}
> +
> +#define TRBE_EC_OTHERS 0
> +#define TRBE_EC_STAGE1_ABORT 36
> +#define TRBE_EC_STAGE2_ABORT 37
> +
> +static inline int get_trbe_ec(u64 trbsr)
> +{
> + return (trbsr >> TRBSR_EC_SHIFT) & TRBSR_EC_MASK;
> +}
> +
> +#define TRBE_BSC_NOT_STOPPED 0
> +#define TRBE_BSC_FILLED 1
> +#define TRBE_BSC_TRIGGERED 2
> +
> +static inline int get_trbe_bsc(u64 trbsr)
> +{
> + return (trbsr >> TRBSR_BSC_SHIFT) & TRBSR_BSC_MASK;
> +}
> +
> +static inline void clr_trbe_irq(void)
> +{
> + u64 trbsr = read_sysreg_s(SYS_TRBSR_EL1);
> +
> + trbsr &= ~TRBSR_IRQ;
> + write_sysreg_s(trbsr, SYS_TRBSR_EL1);
> +}
> +
> +static inline bool is_trbe_irq(u64 trbsr)
> +{
> + return trbsr & TRBSR_IRQ;
> +}
> +
> +static inline bool is_trbe_trg(u64 trbsr)
> +{
> + return trbsr & TRBSR_TRG;
> +}
> +
> +static inline bool is_trbe_wrap(u64 trbsr)
> +{
> + return trbsr & TRBSR_WRAP;
> +}
> +
> +static inline bool is_trbe_abort(u64 trbsr)
> +{
> + return trbsr & TRBSR_ABORT;
> +}
> +
> +static inline bool is_trbe_running(u64 trbsr)
> +{
> + return !(trbsr & TRBSR_STOP);
> +}
> +
> +#define TRBE_TRIG_MODE_STOP 0
> +#define TRBE_TRIG_MODE_IRQ 1
> +#define TRBE_TRIG_MODE_IGNORE 3
> +
> +#define TRBE_FILL_MODE_FILL 0
> +#define TRBE_FILL_MODE_WRAP 1
> +#define TRBE_FILL_MODE_CIRCULAR_BUFFER 3
> +
> +static inline void set_trbe_disabled(void)
> +{
> + u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
> +
> + trblimitr &= ~TRBLIMITR_ENABLE;
> + write_sysreg_s(trblimitr, SYS_TRBLIMITR_EL1);
> +}
> +
> +static inline bool get_trbe_flag_update(u64 trbidr)
> +{
> + return trbidr & TRBIDR_FLAG;
> +}
> +
> +static inline bool is_trbe_programmable(u64 trbidr)
> +{
> + return !(trbidr & TRBIDR_PROG);
> +}
> +
> +static inline int get_trbe_address_align(u64 trbidr)
> +{
> + return (trbidr >> TRBIDR_ALIGN_SHIFT) & TRBIDR_ALIGN_MASK;
> +}
> +
> +static inline unsigned long get_trbe_write_pointer(void)
> +{
> + return read_sysreg_s(SYS_TRBPTR_EL1);
> +}
> +
> +static inline void set_trbe_write_pointer(unsigned long addr)
> +{
> + WARN_ON(is_trbe_enabled());
> + write_sysreg_s(addr, SYS_TRBPTR_EL1);
> +}
> +
> +static inline unsigned long get_trbe_limit_pointer(void)
> +{
> + u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
> + unsigned long limit = (trblimitr >> TRBLIMITR_LIMIT_SHIFT) & TRBLIMITR_LIMIT_MASK;
> + unsigned long addr = limit << TRBLIMITR_LIMIT_SHIFT;
> +
> + WARN_ON(!IS_ALIGNED(addr, PAGE_SIZE));
> + return addr;
> +}
> +
> +static inline unsigned long get_trbe_base_pointer(void)
> +{
> + u64 trbbaser = read_sysreg_s(SYS_TRBBASER_EL1);
> + unsigned long addr = trbbaser & (TRBBASER_BASE_MASK << TRBBASER_BASE_SHIFT);
> +
> + WARN_ON(!IS_ALIGNED(addr, PAGE_SIZE));
> + return addr;
> +}
> +
> +static inline void set_trbe_base_pointer(unsigned long addr)
> +{
> + WARN_ON(is_trbe_enabled());
> + WARN_ON(!IS_ALIGNED(addr, (1UL << TRBBASER_BASE_SHIFT)));
> + WARN_ON(!IS_ALIGNED(addr, PAGE_SIZE));
> + write_sysreg_s(addr, SYS_TRBBASER_EL1);
> +}
> --
> 2.24.1
>
Powered by blists - more mailing lists